Last updated: December 15, 2020
Place
Stop 4: Cross-stratified Sand
NPS/Eric Grunwald
Quick Facts
Location:
41.836498, -103.697783
Amenities
1 listed
Scenic View/Photo Spot
At the set of stairs, look at the cliff face to the left of the trail. The very fine to fine-grained sandstone along this cliff face is cross-stratified or cross-bedded, meaning some of the layering of sediments is at an angle to the main bedding plane.
Cross-bedding suggests that the sandstone here was deposited in an environment where a flowing medium was involved, usually water or wind. Geologists interpret the structures here as products of wind-ripple migration on aeolian dunes.
To continue with the tour, continue down the trail about 75 feet from the concrete stairs. Here we have seen how wind and flowing water can change rock. Do you think living things can affect geologic processes?
Cross-bedding suggests that the sandstone here was deposited in an environment where a flowing medium was involved, usually water or wind. Geologists interpret the structures here as products of wind-ripple migration on aeolian dunes.
To continue with the tour, continue down the trail about 75 feet from the concrete stairs. Here we have seen how wind and flowing water can change rock. Do you think living things can affect geologic processes?